CARONTE

Introduction

Since the end of 2022, CARONTE is a new instrument offered as an alternative to CAMELOT2. CARONTE (from in spanish ‘Cámara de Alta resolución súper Rápida del Observatorio Nocturno del TEide’) is a new high resolution scientific CMOS with 102 Megapixels instrument of the IAC80 telescope, at the Teide Observatory. The IAC80 telescope has 82 cm of aperture and at its cassegrain focus is placed CARONTE, an instrument with a detector made by QHYCCD. It is a 11kx8k back illuminated CCD which operates in the optical wavelength range. It has a huge collection of filters which includes SDSS griz, Johnson UBVRI, Strömgrem uvby standards and many narrow filters. The pixels size is 3.76 μm which implies a pixel scale on-sky of 0.0811 arcsec/pix (binning 1×1). The field of view must be 16 x 12 arcsminutes² 

 Physical characteristics

• Total CCD size: 11656 (horizontal) x 8742 (vertical) pixels
• Pixel size: 3.76×3.76 µm
• Pixel scale: 0.0811 “/pixel (Binning 1×1)
• Binning : 1×1, 2×2, 4×4
• Total CCD field: 16 x 12 arcmin²
• Read modes: 1
• Quantum Efficiency

The detector is a SONY medium format IMX461 sensor, 44*33 mm, 102 Megapixels, back-illuminated, 16bit ADC.

Some other features are:

• Overscan: [47:11712, 114:8841]
• Windows: available in Caronte´s interface.
• Binning: three possibilities of binning are available: 1×1, 2×2, 4×4.

Gain and RON (ReadOut Noise):

Gain 0

Gain 60

Linearity:

The figures below shows the linearity of the sCMOS for the enable readout mode and its gains. The dynamic range of the sCMOS and the recommended flat count in each gain is set from these figures. The characterization procedure has been carried out on the following section of the detector

Gain 0

The linearity of the sensor has been evaluated by plotting the signal—adding the bias level—against the exposure time.

The Photon Transfer Curve (PTC) is used to characterize the response of the sensor to homogeneous illumination, obtaining main features such as the gain–conversion factor between electrons and digital counts (ADU), the full-well capacity (FWC) or the contribution of the different sources to the total noise.

Gain 60

The linearity of the sensor has been evaluated by plotting the signal—adding the bias level—against the exposure time.

The Photon Transfer Curve (PTC) is used to characterize the response of the sensor to homogeneous illumination, obtaining main features such as the gain–conversion factor between electrons and digital counts (ADU), the full-well capacity (FWC) or the contribution of the different sources to the total noise.

Darks:

Dark current is the current generated in photosensitive devices in the absence of light. It is mainly due to thermal generation of charges and is highly dependent on temperature and exposure time. Although the Darks tests shown below have the sCMOS cooled to -20ºC, it is possible to reach -30ºC with the cooler.

Median dark current (DC) for available gains:

Gain 0

Gain 60

PSF (Point Spread Function):

The shape of the PSF (Point Spread Function) along the detector is revised.

Written by David Nespral, GOT